Rodent trap

Abstract

A rodent trap comprises a stiff U-shaped spring with long outstretched arms and wire half-noose that are normally closed tightly together. A folding spreader mechanism at the base of the U-shaped spring holds the long outstretched arms apart until a trigger allows the spreader to fold up. The folding spreader mechanism is prevented from extending over-center and locking like a knee joint as near the point of going over-center, a tiny force like a trigger keeps the folding spreader mechanism extended even against strong spring pressures.

1. An improved trap ( 100 ), comprising:
 a pair of elongated rods in the form of arms ( 102 ,  104 ) biased to close together at their distal ends by a spring ( 110 ); 
 a pair of jaws ( 106 ,  108 ) for capturing a rodent attached to said distal ends of the elongated rods ( 102 ,  104 ); 
 a toggle trip mechanism ( 600 ) for spreading the pair of elongated rods ( 102 ,  104 ) apart to a set position and for releasing them to close when triggered; 
 a trigger ( 128 ) connected to the toggle trip mechanism ( 600 ); 
 the improvement comprising:
 the toggle trip mechanism including an under-center device ( 600 ) connected to spread the pair of elongated rods ( 102 ,  104 ) and jaws ( 106 ,  108 ) apart against pressure from said spring ( 110 ) to a set position without itself locking into a stable over-center position; 
 the under-center device ( 600 ) includes a folding spreader mechanism ( 600 ) having a first spreader arm ( 602 ) pivotally engaged to one of said elongated arms ( 102 ), a second spreader arm ( 604 ) pivotally engaged to the other elongated arm ( 104 ) with a pivot ( 606 ) fixed at its inner section to said second arm ( 604 ), and the pivot ( 606 ) has flanking outer sections ( 612 ,  614 ) that are free to rotate within matching holes in said first spreader arm ( 602 ) wherein in said set position an of the pivot ( 606 ) is above a centerline extending through a center of said elongated arms ( 102 ,  104 ) and a path of travel of said axis from said set position to said close does not cross said centerline; 
 a trigger catch ( 134 ) connected to the under-center device ( 600 ) to provide a sufficient restriction of the toggle trip mechanism until a touch on the trigger ( 128 ) causes the catch ( 134 ) to move and release the under-center device from said set position; and 
 wherein no part of the trap occupies any space between the pair of elongated rods in front of the trigger when the toggle trip mechanism is in said set position. 
 
 
     
     
       2. A trap, comprising:
 a spring ( 110 ) connected to two outstretched arms ( 102 ,  104 ) and such that distal end of the arms ( 102 ,  104 ) are normally closed together; 
 a pair of open half-nooses ( 106 ,  108 ) each of which is perpendicularly attached to said distal ends of the outstretched arms ( 102 ,  104 ), shaped to engage a rodent and such that the open-half nooses remain parallel to one another as the outstretched arms ( 102 ,  104 ) are forced apart and released to close together; 
 a folding spreader mechanism ( 600 ) having a first spreader arm ( 602 ) and a second spreader arm ( 604 ) joined to a common pivot ( 606 ), the folding spreader mechanism ( 600 ) positioned between said two outstretched arms ( 102 ,  104 ) with said first spreader arm ( 602 ) engaged to a base of one of said two outstretched arms ( 102 ,  104 ) and said second spreader arm ( 604 ) engaged to a base of the other of said outstretched arms ( 102 ,  104 ) and providing for a mechanism to force said outstretched arms ( 102 ,  104 ) open and apart in a set position under opposing pressure from the spring ( 110 ); 
 said pivot ( 606 ) disposed in the folding spreader mechanism ( 600 ) to allow the spreader mechanism ( 600 ) to fold to a closed position when said first spreader arm ( 602 ) is fully set on said second spreader arm ( 604 ) with an axis of said pivot ( 606 ) above a centerline extending through centers of said two outstretched arms ( 102 ,  104 ) thereby providing an under-center mechanism to prevent the folding spreader mechanism ( 600 ) from locking said outstretched arms ( 102 ,  104 ) in said set position wherein the path of travel of said axis from said set position to said normally closed position does not cross said centerline; and 
 a trigger ( 128 ) attached to the folding spreader mechanism ( 600 ) such that a touch on the trigger ( 128 ) causes a release of the under-center mechanism from said set position and allows the folding spreader mechanism ( 600 ) to fold to said closed position and allowing said outstretched arms ( 102 ,  104 ) to close and; 
 wherein, no part of the trap occupies any space between the two outstretched arms ( 102 ,  104 ) in front of the trigger ( 128 ) when the folding spreader mechanism ( 600 ) is folded to said set position. 
 
     
     
       3. The trap of  claim 2 , wherein:
 the folding spreader mechanism ( 600 ) includes said first spreader arm ( 602 ) pivotally engaged to said one of said outstretched arms ( 102 ), said second spreader arm ( 604 ) pivotally engaged to said other outstretched arm ( 104 ) with the pivot ( 606 ) fixed at its inner section to said second spreader arm ( 604 ), and said pivot ( 606 ) has flanking outer sections ( 612 ,  614 ) that are free to rotate within matching holes in said second spreader arm ( 602 ). 
 
     
     
       4. The trap of  claim 3 , wherein:
 the spring ( 110 ), elongated rods ( 102 ,  104 ) and said open half-nooses ( 106 ,  108 ) are fabricated from a single piece of spring steel wire. 
 
     
     
       5. The trap of  claim 2 , wherein:
 the folding spreader mechanism ( 600 ) includes a first pivot hole ( 618 ) within and intermediate ends of said first spreader arm ( 602 ), a second pivot hole ( 608 ) within and intermediate ends of said second spreader arm ( 604 ), a pivot pin ( 606 ) extending and rotatable within said first pivot hole ( 618 ) and secured within second pivot hole ( 608 ); 
 whereby the first spreader arm ( 602 ) rotates about said pivot pin ( 606 ) as said first spreader arm ( 602 ) folds over said second spreader arm ( 604 ) to fold to said set position. 
 
     
     
       6. The trap of  claim 5 , further comprising:
 an adjustment ( 137 ) engaged to said first spreader arm ( 602 ) to limit a down stroke of said first spreader arm ( 602 ) when folded with said second spreader arm ( 604 ) to adjust a distance between said axis of said pivot ( 606 ) and said centerline and fine tune a sensitivity of the trigger ( 128 ). 
 
     
     
       7. The trap of  claim 2 , further comprising:
 an adjustment ( 136 ) on said folding spreader mechanism ( 600 ) to engage the trigger ( 128 ) to fine-tune a sensitivity of the trigger ( 128 ). 
 
     
     
       8. The trap of  claim 2 , further including:
 a catch ( 134 ) engaged to said second spreader arm ( 604 ) to hold said second spreader arm ( 604 ) in said set position with said axis of said pivot ( 606 ) above said centerline. 
 
     
     
       9. The trap of  claim 8 , further including:
 an adjustment ( 136 ) engaged to said second spreader arm ( 604 ) and the catch ( 134 ) to adjust a distance between said axis of said pivot ( 606 ) above said centerline to fine tune a sensitivity of the trigger ( 128 ). 
 
     
     
       10. A rodent trap, comprising:
 a spring ( 110 ) connected to two outstretched arms ( 102 ,  104 ) and such that distal ends of the arms ( 102 ,  104 ) are normally closed together; 
 a pair of open half-nooses ( 106 ,  108 ) each of which is perpendicularly attached to said distal ends of the outstretched arms ( 102 ,  104 ), shaped to engage a rodent and such that the open-half-nooses remain parallel to one another as the outstretched arms ( 102 ,  104 ) are forced apart and released to close together against and trap a rodent; 
 a folding spreader mechanism ( 600 ) having a first spreader arm ( 602 ) and a second spreader arm ( 604 ) joined to a common pivot ( 606 ), the folding spreader mechanism ( 600 ) positioned between said two outstretched arms ( 102 ,  104 ) with said first spreader arm ( 602 ) engaged to a base of one of said two outstretched arms ( 102 ,  104 ) and said second spreader arm ( 604 ) engaged to a base of the other of said outstretched arms ( 102 ,  104 ) and providing for a mechanism to force said outstretched arms ( 102 ,  104 ) open and apart in a set position under opposing pressure from the spring ( 110 ), said pivot ( 606 ) disposed in the folding spreader mechanism ( 600 ) to allow the spreader mechanism ( 600 ) to fold to a closed position when said first spreader arm ( 602 ) is fully closed on said second spreader arm ( 604 ) with an axis of said pivot ( 606 ) a distance slightly above a centerline extending through centers of said two outstretched arms ( 102 ,  104 ) whereby a path of travel of said axis from said set position to said normally closed does not cross said centerline thereby providing an under-center mechanism to prevent the folding spreader mechanism ( 600 ) from locking said outstretched arms ( 102 ,  104 ) in said set position; 
 a catch ( 134 ) frictionally engaging said first spreader arm ( 602 ) to prevent said first and second spreader arms ( 602 ,  604 ) from folding when the folding spreader mechanism ( 600 ) is in said set position; 
 a trigger ( 128 ) attached to the folding spreader mechanism ( 600 ) at the catch ( 134 ) such that a touch on the trigger ( 128 ) causes the catch ( 134 ) to disengage from said first spreader arm ( 602 ) and release of the under-center mechanism from said set position and allows the folding spreader mechanism ( 600 ) to fold to a released position and allowing said outstretched arms ( 102 ,  104 ) to close; and 
 wherein, no part of the trap occupies any space between the two outstretched arms ( 102 ,  104 ) in front of the trigger ( 128 ) when the folding spreader mechanism ( 600 ) is folded to said set position. 
 
     
     
       11. The rodent trap of  claim 10 , including:
 an adjustment ( 137 ) intermediate said first and second spreader arms ( 602 ,  604 ) and positioned to maintain said axis of said pivot ( 606 ) a distance above said centerline when the folding spreader mechanism ( 600 ) is in said set position to fine tune a sensitivity of the trigger ( 128 ). 
 
     
     
       12. The rodent trap of  claim 11 , wherein:
 the adjustment ( 137 ) adjusts said distance such that the greater said distance above said centerline the greater the force needed to disengage the catch ( 134 ). 
 
     
     
       13. The rodent trap of  claim 10 , wherein:
 a length of said first and second spreader arms ( 602 ,  604 ) between said pivot axis ( 606 ) and their respective outstretched arms ( 102 ,  104 ) is unequal thereby providing leverage in folding the folding spreader mechanism ( 600 ) to said set position. 
 
     
     
       14. The rodent trap of  claim 13 , including:
 an adjustment ( 137 ) intermediate said first and second spreader arms ( 602 ,  604 ) and positioned to maintain said axis of said pivot ( 606 ) a distance above said centerline when the folding spreader mechanism ( 600 ) is in said set position to fine tune a sensitivity of the trigger ( 128 ). 
 
     
     
       15. The rodent trap of  claim 14 , wherein:
 the adjustment ( 137 ) adjusts said distance such that the greater said distance the greater the force needed to disengage the catch ( 134 ). 
 
     
     
       16. The rodent trap of  claim 14 , wherein:
 the adjustment ( 137 ) adjust said distance such that said axis of said pivot ( 606 ) is above and near said centerline whereby the force of the spring ( 110 ) is applied almost entirely horizontally across said first and second spreader arms ( 602 ,  604 ) with minimal upward force against said catch ( 134 ) thereby enabling the catch ( 134 ) to be disengaged from said first spreader arm ( 604 ) in response to minimal force from said trigger ( 128 ).